<form ng-if="show">
    <input type="checkbox" ng-model="$parent.allData" ng-change="all($parent.allData)">
    <ul>
      <li ng-repeat="item in list">
        <input type="checkbox" ng-model="item.checked" ng-change="ck(item.checked)">
      </li>
    </ul>
  </form>
  <button type="button" ng-click="getShow()">点击</button>
  <pre>
    allData: {{allData}}
    current: {{list}}
  </pre>
